Air conditioner for vehicles



Dec. 1942- 'J. A. NUMERO ETALY 23593935? AIR-CONDITIONER FOR VEHICLES Filed Nov. 16, 1939 8 Sheets-Sheet l Inventors Joseph. A. Numero Frederick MUones.

titer-neg Dw 1942' J. A. NUMERO ETAL 2,303,857

AIR-CONDITIONER FOR VEHICLES Filed Nov. 16, 1939 Sheets-Sheet 3 ON N Inverflrors Joseph. A. Numer-o.

Frederi ck MU'ones. 5 4W I littoras,

Dec. 1, 1942. J. A. NUMERO ETAL AIR-CONDITIONER FOR VEHICLES 8 Sheets-Sheet 4 Filed Nov. 16, 1939 I 7 Jdseph. ANbmero @edeqc M. A /%ne Jones Dec. 1, 1942. J A NUMERQ r AIR- CONDIT IONER FOR VEHICLES Filed Nov. 16, 1939 8 Sheets-Sheet 5 Ubseph A. Numero.

Frederick Tones 5 7 W fierpg.

Fig-1 0 Inve nfo rs:

D 1,;1942. J. A. NUMERO arm. 2,303,857 x V AIR-CONDITIONER FOR VEHICLES Filed NOV. 16, 1939 8 Sheets-Sheet 6 "T8 6i. I

Inventors- Joseph. A, Nun-zero.

P6 QF'LC ones.

Attorney.

Dec. 1, 1942.

J. A. NUMERO ET AIR-CONDITIONER FOR VEHICLES Joseph A.Numero.

Freda rack Mfl'ones B5 WW Khtor-nes Patented Dec. 1, 1942 UNITED- STATES PATENT OFFICE AIR CONDITIONER FOR VEHICLES Joseph A. Numero and Frederick M. Jones, Minneapolis, Minn, assignors to U S Thermo Control Company, an association composed of Joseph A. Numero and M. Green Application November 16,1939, Serial No. 304,796 10 Claims. (Cl. 62-117) Our invention relates to air conditioners for compartments of vehicle carriers and has forits primary object to provide in conjunction with a vehicle carrier, such as a.truck, railroad car or the like, a means of conditioning the air within the compartment of said carrier by tempering, humidifying and circulating the air therein, which means shall be conveniently attachable to and removable from such carrier and which shall automatically efiect the desired air conditioning within the compartment of the carrier.

In the transporting of goods, particularly perishable goods such as vegetables, fruits, eggs, dressed poultry and the like, what is known as trucks have come very largely into use because of their mobility, accessibility for loading, and

capacity for rapid transportation and smooth carriage of their contents. However, even though trucks move largely at night, conditions of weather, particularly hot weather, have presented current of air as it is circulated properly to temper and otherwise condition it.

It is a further important object of our invention to assemble the air circulating and air conditioning means in a unit so constructed that the same may be readily attached to the outside of the floor of the truck, or railroad car, and so attached that it may convenientlybe removed and replaced as conditions may require, thus being at all times readily available for repair, cleaning and replenishment, and at the same time not occupying space in the compartment of the truck or car, which is necessarily valuable for receiving the goods to be transported.

It is a further object of our invention'to provide within the compartment of the truck or car and adjacent a wall thereof. a set of passageways to cooperate with unit passageways of the aforesaid assembled unit such that when the unit is applied to the lower side 'of the floor of the truck, the air may be delivered to the unit from the upper parts of the truck and be forced into the truck after the circulating air has been conditioned.

It is a further object Of our invention to assemble in the unit aforesaid, in a distinctive arorator.

main evaporator heat exchangena blower for moving the air from within the compartment of the truck or car to and past the heat exchanger and back to the compartment of the truck or car,

a condenser and tank for the fluid to be compressed and evaporated, humidifying means, a second blower for cooling the motor and the heated liquid going through the condenser, and various instrumentalities associated with these elements for effecting automatic control thereof.

It is a further object of our invention to provide a housing for the above stated instrumentalities formed of an outside casing and a chamber therein with an arrangement of inner chambers and passageways not only for mounting and holding the various instrumentalities above referred to in a highly compact and conveniently accessible form, but also for providing for such movements of air therethrough as may be desired.

It is a further object of our invention to provide in conjunction with a gas engine, a starter unit controlled by a thermostat within the compartment of the truck or car for turning off and starting the motor when the heat or cooling-demands within the compartment through said thermostat call for it.

It is a further object of our invention to procausing reversal of direction of fluid from the compressor for defrosting the heat exchanger surfaces formed in conjunction with the evap- It will be obvious that the objects enumerated in this and the last paragraph are effected by controlling the direction of flow of the fluid from the compressor. When it goes to the condenser first and then through the evaporator, the air passing through the evaporator coils will be cooled. But when it goes first through the evaporator and then through the condenser the air passing through the evaporator will be heated, so that the ultimate result will be to- 0001 the compartment or heat the compartment according to the direction of flow of compressor fluid.

It is a further object of our invention to provide means for receiving and retaining the water resulting from defrosting and to provide means for maintaining a supply of water of a desired depth subject to current of air going to and-from the truck compartment to aid in suitably humidiac y g said air.

It is a further object of our invention to provide in conjunction with said body of water means.

to cause the partially heated refrigerant liquid to pass through coils within said body of water to prevent freezing thereof and increase its capacity for evaporation.

It is a further object of our invention to provide an electric heater in association with said body of water and controlled by a humidostat in the truck compartment to increase the amount of water vapor in the air ofthe truck compartment.

Other objectsand the full advantages of our invention will appear in connection with the detailed description thereof and the novel features by which the advantageous results following the practice of our invention are secured, will be particularly pointed out in the claims.

In the drawings illustrating an application of our invention in one of its forms:

Fig. 1 is a perspective view of the unit as the same would appear when attached to the lower surface of the floor of a transport carrier such as truck or van, the floor being shown broken away.

Fig. 2 is a. sectional elevational view taken on line 2-2 of Fig. 3 when the unit is attached to the underside of the floor of the truck and also taken through parts of the truck shown broken away to show the air circulating ducts within the truck compartment.

Fig. 3 is a sectional plan view of the unit with some parts broken away.

Fig. 4 is a detail plan view on an enlarged scale of the reversing valve for the compressor, some parts shown in section and broken away.

Fig. 5 is a central sectional elevational view through the valve casing and reversing valve showing the motor for operating it.

Fig. 6 is a sectional view taken on line 6-6 of Fig. 5 viewed in the direction of the arrows.

Fig. 7 is a sectional view on an enlarged scale (full size) taken on, line 11 of Fig. 5 viewed in the direction of the arrows.

Fig. 8 is a vertical sectional view taken on line 8-8 of Fig. 5 viewed in the direction of the arrows.

Fig. 9 is a top plan view of the rotatable valve member only.

Fig. 10 is a sectional plan view taken on line i8- -l0 of Fig. 3 viewed in the direction of the arrows.

Fig. 11 is a transverse elevational view taken on line "-11 of Fig. 1.

Fig. 12 is an enlarged sectional view taken on line l2-l2 of Fig. 1l for showing the means for securing the unit removably to the underside of the truck floor.

Fig. 13 is a transverse sectional view on line l3-l3 of Fig.3 viewed in the direction of the arrows on a somewhat enlarged scale.

Fig. 14 is an enlarged sectional fragmentary view taken on line l4-l4 of Fig. 3.

Fig. 15 is a fragmentary sectional view of a part of the blower chamber taken on line l5-'-l5 of Fig. 3 and Fig. 13.

Fig. 16 is a schematic view in plan showing the various instrumentalities and their relations one to the. other.

Fig. 1'1 is an enlarged detail sectional view of the feed valve mechanism.

Fig. 18 is a schematic wiring diagram showing the relation of the diflerent electrically operating instrumentalities.

As shown, a main casing 29 of generally recside walls 23 and 24 and end walls 26 and 26.

The box-like structure resulting from the combination of these walls is rigidly reinforced and developed into a very strong cell-like structure by means of partitions later to be described and also by transverse U-pieces 31, 32, and other reinforcing bars and partitions. An inverted pan having a top wall 2| and depending flange portions 21, 28, 29 and 30 (see dotted line Fig. 10) is adapted to be secured .to the outside of the floor of the truck or car. Riveted to end walls 23 and 24 are strap plates 33, Figs. 2, 11 and 12. These strap plates are formed with semi-circular extensions 34 providing a recessed seat 35 adapted to receive a semi-circular bar 36 as clearly shown in Fig. 12. The extension 34 may be formed with a slot 31 for a purpose hereinafter to be described.

Upon the ends of plate 21 are secured by welding or otherwise reinforcing plates 38, Figs. 2, 11 and 12, which preferably will be countersunk into the outside bottom of the truck or car with which the apparatus is employed. As shown in Figs. 1 and 11 these bars have their ends turned outwardly at 39 and 40 overlying the flange portions 21 and 29. This arrangement is such that the upper edges of the casing 20 may be inserted in contact with the flanges 21, 28, 29 and 30 and the strap plates 33 in alinement with downtumed portions 39 and 40 of the reinforcing plates or bars 38.

Each of the turned down ends 39 and 40 is provided with a cylindrical loop 4| in which is mounted a pin 42 having secured thereto, by means of a thumb screw 43, the hub 44 of a threaded shank or bolt 45. The bolt 45 is adapted to swing through the slot 31 in the semi-cylindrical member 38 and pass through an opening in keeper bar 36. Nuts 46 threaded onto the bolt 45 engage the keeper bar 36 and by this means firmly secure the casing 26 and the parts carried thereby to the bottom wall of the truck or car indicated generally at 41 of Figs. 2 and 11. Suitable rectangular duct extensions 48 and 48, Fig. 2, of a. relatively narrow and long cross section as indicated in the schematic diagram of Fig. 16 are secured to plate 2| and are adapted to be projected through openings in the truck floor 41 close to a side wall of the compartment within the truck. These duct extensions are thereby brought within corresponding ducts 50 and II, Fig. 2, which extend along an inside wall of the truck compartment. Duct-50 which is the duct for withdrawing air from the truck or car, is preferably provided with extensions 52 and 53, close to the top of the compartment; which open as at 54 into the body of the compartment near the ends thereof. The duct 51 carries the air from the air conditioner assembly into the compartment and may advantageously discharge, as indicated at 55 at a point toward the upper part of the compartment. 9 r

A thermostat control device 56 is located at a suitable point within the compartment. This has a cable 51 running down a wall of the compartment and through the floor 41 and is provided with a plugging socket'58 which through a cable 59 extending through an insulated block 60 in end wall 26, is adapted to connect the thermostat with controls :later to be-described. A humidostat 221, later to be described, is similarly connected.

From the above description it willbe apparent that the casing 28 and parts carried thereby can readily be attached to and detached from the bottom 41 of any transport vehicle. In practice the plate 2| will first be attached to the bottom of the vehicle with the ducts 48, 49, extending through openings therein as indicated in Fig.1. The main casing will be placed on blocks which will bring its upper edge below the depending edges of flanges 21, 28, 29 and 30. The casing will then be placed into position under the vehicle. The screw arms 45 carrying the keeper bars 36 will be swrmg through slots 31 so as to bring the keeper bars within the semi-circular seats 35. The several nuts 46 will then be screwed up to bring the unit tight against the underside of plate 2I.

In similar manner when it is desired to remove the unit, the vehicle will be positioned as desired and the unit will be released to the receiving blocks or horses by unscrewing the nuts until it rests thereon.

Within the casing 20 a series of partitions divide the space so as to provide certain chambers for receiving the different instrumentalities by means .of which the air conditioning system is carried out. A rectangular set of partitions 6 I, 62, 63, and 64, Fig. 3, extend from top to bottom of the chamber formed within casing 20 and enclose the air cooling chamber65 connected with duct outlet 48 and blower chamber 56 connected with air duct 49, the two chambers 65 and 66 being separated by partition I0, Figs. 2 and 3, and the end wall II of evaporator heat exchanger I2 which is connected to partition I and supported at one end thereby and is supported at its other end by an angle iron 13 secured to wall 63. As clearly shown in Figs. 2 and 3, the evaporator heat exchanger comprises a multiplicity of interconnected pipe members I4 which normally receive refrigerant for.-evaporation through pipe I connected through a pipe I, later to be described, with the refrigerant tank 16 and passes the expanded and evaporated gas from this evaporator through a pipe 11, a special valve construction 18 later to be described, and through pipe I9 to compressor 80. As clearly shown, heavy insulation indicated at 8I in Figs. 2 and 3 is placed about the walls 6|, B2, 63, and 64 forming the combined chambers 65 and 66 and also under a bottom wall 82 of said chambers. A second set of partition walls 83, 84, 85, and 86 encloses the side insulation ill and a second bottom wall 81 encloses the bottom insulation.

As shown in Fig. 2, the chamber 65 is connected with chamber 66 by a bottom chamber 88. A

blower 89 of well known construction is in chamber 66 positioned adjacent the outside of the casing, as clearly shown in Fig. 3. The lower part of chamber 66 is separated from the upper part by the blower casing 90, supporting partition 9I and Referringto Figs. 3 and 10, it will be notedthat partitions 83, 84, and additional partition 93 between partitions 84 and the side wall 24, forms a main chamber 94 with an L-shaped extension chamber 95, which chambers are, as above pointed out, thoroughly insulated from the air cooling chambers 65 and 66. Within main chamber 94 is a gas engine 91 of common construction withilts exhaust manifold 98 delivering outside of casing 20 at 99. A main motor shaft I00 has thereon a multiple grooved pulley IOI. A multiplicity of belts I02 runs over multiple pulley IM and a multiple pulley I03 on the shaft of compressor 80, which is of well known construction, and by which the compressor 80 is driven. Thewater circulation pipe I04 goes to radiator I05 located in a chamber I06 at the rear of the casing, Figs. 3 and 10. In a portion 'I0'I of said chamber extended alongside of insulated air cooling chamber 65 is a gasoline storage tank I08 adapted to be filled from the outside, as indicated at I09 Fig. 1, through a pipe IIO. A water filling cu'p III, Fig. l, is also provided for adding water to the cooling system at the top of the radiator through pipe I I2, as indicated in Figs. 1 and 2. For convenience, as shown, the gasoline feed pipe H0 is carried through the insulation between partition 63 and 85, Figs. 2 and 3. A water inlet pipe II 3 carries the Water through a pump in the engine casing, not shown, through the cooling passages of the motor and through pipe I04 back to the radiator.

The detailed arrangement of radiator I05 in relation to condenser coils I I4 is shown in Figs. 2, 3, 10 and 11. As there shown, the condenser II4 faces an opening H5 in the front of the casing member 20, which opening may, if desired, be protected by a grating or grill The radiator I05 extends along the side 23 of the casing 20 facing an opening H6 in said side as best shown in Fig. 3. Elongated top and bottom water chambers H1, H8 are formed by casing extensions *9, I20 shown in vertical cross section in Fig. 11 and in plan cross section in Fig. 3. The inlet pipe I04 from the motor enters the end of extension I I9 as shown in Fig. 10 and the outlet pipe H3 going to the pump of the motor leaves the other extension I20.

The above set of instrumentalities, including a battery 'I2I, that is, a gas tank I08, the radiator I05, the .condenser H4, and the battery I 2i, are housed in a separate L-shaped compartment at the front of the casing 20 which is entirely segregated from the other two compartments within the casing, namely compartments 94, 95 for the gas engine and compressor and associated parts, and insulated air cooling compartment and 66. Thus the engine and compressor compartment on the one hand and the radiator and condenser compartment on the other, are each available to be cleaned as desired independently of the air cooling compartment. A door I22 admits to one side of the engine compartment-and a wide door 123, Fig. 3, admits to the other side of the engine compartment and to a blower I24 between the compressor compartment and the radiator and condenser compartment, which is driven from a pulley I60 on the motor shaft I00 .and a belt HiI running over a pulley I62 on the shaft I63 of the blower rotor I24.

Figs. 3 and 10 show the position and means of operation of this blower wherein the blower casing I25 opens through the side 22 as indicated at I26 of Fig. 10. The blower draws air into its central opening I 27 through radiator I05 and condenser coils II 4 and discharges it outside of the casing through the opening I26. At the same time the casing I25 has a screened opening I28 wise controlled opening I29 at the rear of easing 20, as shown in Fig. 3, thus taking away the external heat of the compressor and motor. The blower 89. Fig. 1 is driven by a pulley I30 on an extension I3I of the motor shaft through a belt I32 running over a pulley I33 on the shaft I34 of the blower rotor I25. A generator starter I35' of distinctive construction'is adapted to operate the motor 91 subject to control by thermostat and pressure means later to be described.

The compressor 80, of standard construction, is mounted on a stand I64 shown in detail in Fig. 13. In practice the refrigerant tank 16 is preferably cylindrical and fits between depressed portions I65 and I66 of the stand I64 which engage the tank with a degree of pressure to hold it firmly positioned without other means. As heretofore pointed out, the compressor is driven through multiple belts I02 over large multiple grooved pulley I03 on the compressor shaft I61, Fig. 10. The compressor 80 receives the returned gas in manifold I36 from pipe 19 and delivers the compressed fluid from manifold I31 through pipe I38. As already pointed out, the refrigerant fluid is delivered to the evaporator heat exchanger 12 through a pipe 15. This pipe leads through a double valve structure I39, I40, and a connecting pipe I4I from the fluid refrigerant tank 16. The details of this valve structure are shown in Fig. 17 and its purpose will be related to the reversal for defrosting later to be described. As shown in Fig. 17, valve I39 comprises an ordinary check valve and is in direct line I 4| with a branch pipe I42 which connects with the pipe 15. Obviously when the pressure is direct from the tank 16 the check valve I39 will be closed by that pressure and prevent movement of fluid from pipe section I42. The valve I 40 is in a branch pipe line I43. This valve embodies a spring pressed needle valve I41. When the pressure of the fluid coming through pipe I from tank 16 is sufficient to overcome the force of the spring I40 tending to hold valve I41 closed,.a jet of fluid will'pass the needle valve I41 and through pipe connection to the evaporator coils 14 where its evaporation will take heat from the fins about said coils and from the air passing over them to provide the cooling desired.

This evaporation may, and frequently will, cause frosting on the coils and fins to such an extent as to restrict travel of air through the heat exchanger. When this happens the reduced air pressure in the chamber 88 below the heat exchanger 12 will operate the aneroid I50 causing an electrical contact at I 5| which, through wire I52 will operate the reversing valve in a manner later to be described and cause the fluid to flow in the opposite direction, that is the hot fluid through heat exchanger 12 from compressor 80 and the cold fluid through condenser I I4 back to the compressor. The details of this valve structure are shown in Figs. 4, 5, 6, 7, 8 and 9 and will now be given.

The valve chamber 18 comprises a vertical cylindrical member into which leads the pipe I38 from the compressor manifold I31 and the pipe 19 to the compressor manifold I36. Also connected with the valve casing 18 is pipe I68 runningfrom the condenser to the valve casing and entering the valve casing 18 in a vertical plane directly above the entrance of pipe member I38 going to the compressed gas manifold. Referring to Figs. 4, 5, and 16, and particularly to Fig. 4, and assuming that the fluid is moving in the normal direction for entering the evaporator and effecting cooling heat exchange therewith, it will be noted that the hot compressed fluid from manifold I31 goes through pipe'I38 into the valve chamber containing the valve block I10 from where it is caused to move through pipe I68 to condenser II4 where it is cooled. From the condenser II4 the fluid flows through pipe I69 and directly through sets of valves I1I, I12, similar to valves I39, I40, wherein the check valve I12 is in position to permit free flow of the fluid through the pipe and into the compressed refrigerant tank 16. From the tank 16 the fluid, after it passesvalve I40, goes through pipe 15 into the evaporator heat exchanger 12. From there it goes through pipe 11 into valve member 18 and from there throughpipe 19 to the intake manifold I36 where it is again subjected to the action of the compressor.

The above operation is one in which the gas, after it enters the valve from feed pipe I38, takes the direction indicated by the dotted arrows of Fig, 4, first to the condenser, then to the tank,

then to the evaporator and back through the valve and pipe 19 to the receiving manifold I39. When however, it is desired to reverse the flow for defrosting, the travel of the hot gas will be as indicated by the full line arrows of Fig. 4. That is, when the hot gas enters the valve casing with the parts as there shown in section, it passes, as indicated by the arrows, through pipe 11 to the evaporator heat exchanger 12, thence through pipes 15 and I to the tank 16, thence through pipe I69 to and through the condenser I I4, thence through pipe I68 to valve I40 and from there through pipe19 to receiving manifold I36.

The change of direction of flow while the motor and compressor are in constant operation, is effected by a cylindrical valve piece I15 which is adapted to be oscillated a quarter of a turn back and forth to bring about this result. Having reference to the drawings, Figs. 5, 7 and 8, 9, it will be noted that valve block I15 is cylindrical in outline, and is seated within a cylindrical cavity I16 in a valve block I11 which underlies the valve block I10. The rotary valve member I15 is fast on a vertical shaft I18, which is driven by means hereinafter to be described, and the opening through which the shaft extends to chamber I16 is sealed by a sealing washer I19 pressed upward by a spring I80 and connected in gas-tight relation with an accordion or corrugated drum I8I. An annular chamber. I82 is formed inthe lower portion of. rotary valve member I15, Figs. 5 and 7, and the hot fluid pipe I33 leading fromthe hot gas manifold enters this annular chamber I82, as clearly shown at I33, Fig. 5. Thus the hot gas comes to the valve chamber always in the same way as it necessarily would have to do, and is reversed in direction of flow from the valve by the change of position of the rotary valve member I15, always leaving the valve chamber through pipe 11 which conveys the fluid back to the receiving manifold I36.

This is accomplished by the following means:

Referring to Figs. 5 and I, the valve block I13 embodies adownwardly turned channel I85 presented to the face of rotary valve block I15 and connected with the pipe I68 which leads to the condenser. Also within the valve block I10 is a the fluid from the evaporator heat exchanger to the valve or from the valve to the evaporator heat exchanger according to the position of the member I15. A fourth channel I90 formed in block I extends in an arcuate direction, as shown in Fig. '1, from channel I85 to a downwardly opening channel I81 which fronts the top ofrotary valve I and connects with channel I90 in the manner shown in Fig. 7 in full lines and in Fig. 8 in dotted lines.

The rotary valve I15 is provided with an opening I92 all the way through, as shown in Figs. 5 and 9. which therefore at all times is open to the annular passageway I82 about the bottom portion of rotary valve member I 15. The opening.

I92 is preferably arcuately oblong in cross section in order to avoid complete blocking of compression in the shifting of the valves which might cause jamming or chattering. The cross sectional form of the opening I92 is shown in Fig. 9. Also there shown as related to the longitudinal opening I92 is an arcuate channel I93 which is shown in plan in Fig. 9 and in cross section in Fig. 8, as there related to the channel I88, also shown in dotted lines in Fig. 5.

As the parts are shown in Fig. 5, which is the normal position for refrigerating, it will be noted that the hot compressor gas comes into the channel I82 from pipe I38. From the annular channel I82 it passes through opening I92 into pipe I88 from where it goes through the condenser I I4, from the condenser through pipe I89 to the tank 18, from the tank 18 through pipes MI and 15 to the evaporator heat exchanger and from the evaporator heat exchanger through pipe 11, see Figs. 5 and 8, into the valve block I10, through channel I88 to the arcuate channel I93 from which it travels through channel I88 to pipe 19 and from there back to the inlet manifold of the compressor. This also is fully illustrated in Fig.

' 7. When however, the valve member I15 is turned a quarter of a turn to the left, the vertical channel I92 will come under the opening I88 leading to the pipe 11. At the same time the depressed channel I93 in valve I15 will move to extend between openings I88 leading to pipe 19 and I81 connected with arcuate channel member I90. When the parts are in this position the hot gas coming through pipe I38 from manifold I31 will pass from annular passageway I82 up through vertical passageway I92, passageway I88 and through pipe 11 directly to the evaporator heat exchanger where its heat will quickly cause defrosting of the refrigerant coils there. From the evaporator heat exchanger, as shown by the full line arrows of Fig. 4, the fluid will pass through pipes 15 and iii to the tank 18, through pipe I89 to the condenser and through pipe I88 back to the valve. At the valve it will flow through arcuate channel I90 and vertical channel I81 in block I10 into arcuate channel I93 in valve member I15 and from there through passageway I88 to pipe 19 leading to the receiving manifold of the compressor.

From the above description it will be apparent that in the dual operation, for normal refrigerating and for defrosting, the refrigerant tank in effect occupies a position between the evaporator and the condenser. The check valve I39 during refrigerating operation prevents free flow from the tank to the compressor so that the gas has to be forced through the valve I40 thus determining the delivery pressure to the -evaporator. In the reverse or defrosting flow, valve I39 permits free points 201 and 208. Contact ried by a bracket 209 fast on plate I98 and con-' I", similar to the valve I39, I40, is placed in the pipe line I89 between the condenser H4 and the refrigerant tank 19. In normal or refrigeration operation the check valve I12 permits free flow of refrigerant from condenser I I4 to the refrigerant tank 18. But when the valve 19 has been operated. to reverse the now for defrosting, the check valve I12 blocks free flow from the tank to the condenser and the liquid will have to flow through the pressure valve I1I thus determining the pressure at which the refrigerant goes to condenser I I4.

Each of the valves MI and "I has the pressure .delivery past it determined by the needle valve I41 actuated by the manually controlled spring I49, so that the pressure deliveries may be made uniform for each direction of flow of second pressure valve the refrigerant. It will thus be apparent that the system is balanced in operation for both normal flow of refrigerant from the tank to the evaporator in refrigerating operation and for reverse flow from the tank to the condenser in the defrosting operation.

In the latter, the condenser becomes an evaporator and is intensely cold so that the air drawn through it will temporarily chill the first chamber 95, by reason of air passing through grating I29 of blower casing I25, see Fig. 3.

The block I10 is carried by a bracket arm or plate I94, Fig. 8, to which the block is secured by a series of bolts I95, Figs. 7 and 8, as clearly shown in Fig. 8. The bolts I95 go through the block I10 into the second block I11 securing the whole assemblage together to the supporting bracket I94. This bracket I94-has a vertical lip 204 secured by strong bolts 205 to a wall 83 of the tank, see Figs. 2 and 3. A bottom bracket plate I98 having the plan outlined, clearly shown in Figs. 6 and 7, is secured to block I11v by screw bolts I91. To the bracket plate I98 is secured a frame piece I98 by means of bolt I99, and by a surrounding strap 200 an electric motor 20I is supported from plate I98. Projecting from motor 20I is a gear box 202 into which extends the vertical shaft I18 connected with the rotary valve member I15. Through reducing gearing within gear box 202 (not shown) the motor 20I slowly rotates the shaft I18 to give the same one quarter turn in one or the other of the directions to cause the passages and ports to'register, as in Fig. 5, or in its other position. Upon shaft I18 is mounted a contact arm 208, shown in Fig. 6, which is adapted to oscillate between contact point 201 is cartact point 208 is carried by a bracket 2I0 fast on plate I98. Contact point 201 operates means to 'open and close the circuit between wires 2 and 2I2, and contact point 208 operates means to open and close the circuit between wires 2I3 and 2M. The motor 20I is a standard reversing motor with two sets of current wires 2I5, 2I8 and 2H, 2 I8. As already pointed out, the aneroid I50 is caused to expand when frosting so blocks the air passage that substantial negative pressure is set up in the chamber 85 below evaporator heat exchanger 12. This closes electric circuits in a manner later to be pointed out, and causes enerflow to the tank. A second check valve I12 and gization of the motor 20I in the direction to carry the arm 208 from whichever one of contact points 201 or 208 it may then be engaging to the otherof said contact points.

The defrosting of the evaporator heat exchanger 12 wvill necessarily result in a release of a considerable quantity of water. We employ this for re-evaporation in conjunction with other means for providing water vapor so that suitable humidification of the truck compartment may be effected at all times. As shown in Figs. 2 and 13, a pan 2I9 is provided which overlies the entire floor 82 of the combined msnlated chamber 65, 66. A waste trap 220 is adapted to release surplus water at a predetermined depth, as clearly indicated in Fig. 2. The pan will be filled with a layer of fibrous substance preferably mineral wool, which extends above the surface of the pan as indicated at 2'2I. If desired the pan may be omitted and the bottom of chamber 88 be used as a pan. In either case the height of water retained will be determined by the height of the waste trap tube 220. As clearly shown in Fig. 16, the pipe I4I from the refrigerant tank is carried in coils I4Ia along the bottom of pan 2I9, which results in additionally cooling the refrigerant on the way to the evaporator through pipe 15, which is desirable, and at the same time sufllciently warming the water in pan 2I9 to prevent any possibility of freezing and to increase its capacity for evaporation. In addition to receiving the water which runs down from the defrosting action, the

pan 2I9 will receive water from a pipe 222 Fig. 13, which is connected with a filling cap 223 extending through side wall 213. By this means the pan 2I9 will be filled with water before the refrigerating mechanism is started and excess water will drain off through trap drain 220.

For furnishing additional quick moisture an electric heating element 224 of standard immersion construction is positioned in the pan 2I9, as indicated in Fig. 13, at a point closely adjacent the opening 225 into the blower I25. Electrical connections 226 go from the heating element 224 to a humidostat 221 of standard construction located in the vehicle compartment as indicated'in Fig. 2 and connected in the electrical wiring system by lwiring cable 228. By this means the heater 224 will only operate when there is a call for humidification within the vehicle compartment and will be put out of operation when the air in the vehicle compartment at any temperature is sufficiently humidified.

In practice, the pan 2 I 9 will be filled with water before the cooling apparatus is set in operation.

When this is eflfected, through control box 229 current will immediately be supplied to the heater 224. This heater is positioned near the top of the surface of the water with very little water surrounding it and will immediately give oif a quantity of water'vapor which is carried up into the truck compartment before any substantial frosting can take place.- In this manner the air in the truck compartment will be rendered humid. As frosting takes place on the evaporator heat exchanger more moisture goes to the compartment both by reason of the action of the heater 224 and because of evaporation into the current of air from the flbrous material 22I of water warmed by pipe coils I4Ia. The result is that as fast as moisture may be taken from the air by frosting it is restored to the air within the truck in the manner described. It at any time the air within the truck reaches a high degree of humidity, approaching substantial saturation, the humidostat 221 will break the circuit to the heater 224 and only such moisture as comes from evaporation on the fibrous material 22I will then go to the compartment. By this means the compartment of the truck will have its air maintained in a substantially saturated condition of humidity and there will be no tendency to withdraw moisture from any of the load contents of the truck compartment.

Considering the wiring diagram Fig. 18, the thermostat 56 may comprise an expansion member 232 with a movable contact 233 connected with wire 234 and adapted to engage a fixed contact 235 connected with a wire 236. The

10 contacts 233 and 235 will be normally in engagement and are only separated when the temperature within the truck compartment reaches the desired low degree, when the contraction of member 232 will cause separation thereof, and

stop operation of gas engine and compressor.

Several safety devices are employed. Wire 234 goes to a contact member 231 carried by a thermostat arm 238 in a box 239. The contact member 231'is normally in contact with a contact member 240 which is connected with a wire 24I.

If for any reason the engine heats unduly, thermostatic member 238 will move to break the contact between members 231 and 240 and the motor 91 will thereby be stopped. Wire 24I goes to a movable contact member 242 which engages a contact 243 connected with a wire 244. The movable contact piece 242 is pivoted at 245 and is held in contact with member 243 by a spring 246. A pressure tube 241 runs from the hot fluid manifold I31 of compressor 80 to a pressure responsive device 248 having a plunger 249 adapted to engage an arm 250 fast with the movable contact arm 242. When the pressure in the compressor system rises to approach the danger point 5 the plunger 249 will engage the arm 250 and break contact between contact members 242 and 243 thus stopping the gas motor and the compressor. A gauge 250 in the instrument control box 229 is connected by a branch pipe I with the pipe 241 and indicates to the operator the pressure at which the compressor is working. A low pressure tube 252 leads from the -low pressure manifold I35 of compressor 80 to a pressure responsive device 253 which embodies a plunger 254. An arm 255 is caused to engage the end of plunger 254 by means of a spring 255. There is an arm 251 movable with arm 255 about a point of pivoting 258, and when the pressure within the system drops to indicate blocking from freezing, the spring 255 will be permitted to rock arms 255 and 251 so as to bring arm 251 against arm 250. and also break the contact between members 242 and 243. A gauge 259 on a branch pipe 250 connected with pipe 252 indicates to the operator the reduced pressure at which the system is working. The wire 244 is connected through branch wire 2" with a high tension coil 262 which is connected through cable 253 with the'distributor in the usual way, and wire 244 is also connected with 5 contact 256 on a spring-held double contact arm the windings .of a relay 254 for a purpose hereinafter to be described. The second wire 235 running from the thermostat contacts 233, 235, goes to a contact 255 which normally engages a 261 secured to frame piece 253 and connected to a wire 269. The wire 269 passes through a resistance winding 210 which engages a thermostat piece 21I. A hook 212 on thermostat piece 21I engages the hook 213 connected with double arm 261. This resistance winding 210 is in a branch circuit including a wire 215 which runs to a contact member 216 adapted to engage another contact member 211 connected by a wire 213 with a relay 295 and from the relay 295 with To order to reverse the operation of motor 20! it ground 286. The purpose of this arrangement will be later described, but the object of the thermostatic member 21! and heatingmesistanceflf 261, past contacts 265, 266 through wire 236, past contacts 235, 233, through wire 234, past contacts 231, 240, through wire 24!, past contacts 242, 243, through wire 244 to relay 264 and finally to ground 28!, thus energizing relay 264 and closing contacts 282. This causes heavy battery current to pass through wire 284 to and through relay 285 and thence through wire 286, through the field coil 281 of the starter motor armature 288 and to ground 289. At the sam time current will pass through a rheostat 290 and wire 29! through generator field coils 292 and thence through wire 293, to the armature 288, thereby caused to generate current going through battery I2I.

The relay 285 has only a few windings which will be sufficient when the heavy battery current from wires 289, 284 passes through it to operate armature 294 and thereby send current through closed contacts 216, 211 and wire 218 through relay 295 to the ground 296, which through lever system 291 will operate the choke valve 298. As soon as the motor 288, however, has started, generator current will move back over wire 286 through relay 285, wire 284, contact 282 and main battery wire 289 to the battery. This current will be much weaker than the strong battery current and will result in releasing armature 294 and breaking contact 216,211, with the result that the choke valve 298 is released to normal position, and resistance winding 219 is put out of circuit entirely. At the same tim current is passed from wire 244 through wire 26! and high tension coil 262 to ground 299. As shown in the upper portion of Fig. 18, the lever system 291 includes a bimetallic thermostatic arm 339 which has apin 33! operating in a slot 332 in a link 333 forming part of said lever system. With this means, when the engine is hot the thermostatic action of arm 339 will move pin 33! down slot 332 so that relay 295 will not have any effect on choke valve 298.

The electrical hook-up for operating the rotary valve I to cause reversal of flow of refrigerant for defrosting is shown in the lower right hand portion of the wiring diagram of Fig. 18. When the air passages about the evaporator heat exchanger 12 become so clogged with frost as to block or partially block flow of air therethrough, the reduction in pressure within passageway 88 in the lower part of chamber 65 will cause the aneroid I50 to expand bringing the contact member I5! in engagement with a contact piece 399 connected with a ground 39!. This permits battery current to flow through a branch wire 392 through a relay 393 and a wire 394 from said relay to the ground 39!. Operation of the relay armature 305 will close contacts 306, 301 and 308, and open contacts 309, 3I0 and 3! I.

The motor 20! may be considered as formed of its two parts, the field coil 3 I2 and the armature 3l3; the wires 2I5 and 2!6 connect with the field coil 3! 2, and the wires 2 and 2!8 connect with the armature 3I3, wire 2 !8 going to ground 3I4'.

. is necessary to reverse the direction of current through the field windings 3 I 2, and this is effected by the shifting of contacts 396 to 3!! inclusive.

All the partsas shown in the lower right hand portion of Fig. 18 are as they would be'for normal refrigerating action, that is, with contact members l5! and 300 out of contact and armature 395 inactive and contacts 309, 3! 0 and 3!! closed. Also the arm 206 has operated at the end of its half-turn to break contact between wires 2l3 and 2 at the point 3l5. When however, the defrosting action-is called for because of contact between members !5! and 390 and relay 393 has broken contacts 309, 3l9 and 3!! and made contacts 306, 301 and 398, battery current will pass through wire 3I6 and wire 2I2 across the closed contact 3I1 through wire 3l8 across contact 308 to wire 2 I 1 and thence to motor armature 3!3-- to ground 3. At the same time current will go from wire 2I1 through wire 3I9 across closed contact 396, through wire 329 and wire 2l6 in the direction of the arrow marked a, to and through the field coil 3!2 to wire 2l5, through closed contact 301 and through wire 32! to ground 322. This will operate the motor 29! to cause arm 206 to travel from plunger 208 to plunger 291 which will break the circuit at 3" terminating operating of the motor. At the same time the rotary valve. I15 will have been moved from its position for passing the refrigerant normally for refrigerating action to its position for reversing the flow of refrigerant to eflfect defrosting.

As soon as the defrosting operation has reopened the air passages through evaporator heat exchanger 12, which will occur very quickly, the air pressure in passageway 88 will increase with the result that the aneroid I59 will contract, breaking the contact between arm !5! and contact piece 390. This will de-energize relay 393 whereupon the armature 395 will take its inoperative position and contacts 309, 3m and 3!! will be re-established. This will permit battery current to pass through wire 3I6 and wire 2! 4 across the closed circuit at 3|5 to wire 2I3, across closed circuit 3!! to wire 2 and thence through motor armature 3!3 to wire 2I8 to ground3l4. At the same time current will pass through wire 3l9,- closed contact 309 and wire 2I5 to the field coil 3l2 and thence through wire 2I6, moving in the direction indi cated by the arrow marked b, through wire 323 through closed contact 3I9 and wire 32! to ground 322. The direction of current through field coil 3 I 2 is thus reversed which operates the motor 29! in the opposite direction, with the result that arm 206 travels back to the position indicated, breaking the circuit 3! 5 and thereby terminating operation of the motor. At the same time the valve I15 will have been restored to normal position passing refrigerant through the evaporator heat exchanger 12 to eifect cooling of the air passing through said evaporator heat exchanger.

As shown at the central left of the diagram of Fig. 18, a wire 324 leads from the wire 236 to the water vaporizing heater 224. From the heater 224 the wire 226 leads to the humidostat 221. The

will be so adjusted that the breaking of contact will only occur when substantial moisture saturation of the air within the vehicle compartmenthas taken place. The main switch 328 operated from the control box 229 is adapted to turn on and oil electrical connections for controlling operation of the entire system.

The advantages of my invention will sufficiently appear from the foregoing description. A primary advantage is that a compact, eflicient and not too heavy assemblage of instrumentalities is provided, which is adapted readily to be attached to and removed from the outside of a transport vehicle such as-a truck or railroad car,

and which, when attached, cooperates with means within the vehicle compartment for causing a circulation of properly conditioned air to, through and from, the compartment. The primary conditioning effected is for cooling the air within the vehicle compartment, with means for rendering such cooling continuous and within proper temperature limits, and at the same time vehicle, and for making practically effective the operation of an air conditioning unit adapted to be removably attached to a transport vehicle.

We claim: 1. Means for air-conditioning compartments adapted to hold moisture-containing perishables,

' comprising means for circulating air in such compartment, means for cooling said air including an evaporator heat exchanger and a compressor, means controlled by the pressure of said current of air for'causing reversal of the flow of refrigerant to defrost the evaporator heat exchanger, and means for causing addition of moisture to the said current of air proportional to the amount of moisture withdrawn therefrom by frosting.

2. In means for removably securing an airconditioning unit to the outside of a compartment of transport vehicles such as trucks in cooperative relation with air ducts within the compartment adapted to permit withdrawal of air from one portion of the compartment and delivery of air into another portion of the compart ment, comprising a plate adapted to be attached to a wall of the vehicle having duct extensions passing through openings in said wall and forming continuations of said first-named air ducts, said plate formed with surrounding depending flange members forming an inverted box, a rectangular open-topped box having its upper portions adapted to fitwithin the inverted box formed on the plate and. housing an assemblage of airconditioning instrumentalities for cooperating with said ducts, and means for removably securing said last-named box to the plate and inverted box with the edges of the last-named box engaging the plate within the inverted box.

3. Means for air-conditioning compartments adapted to hold moisture-containing perishables, comprising a housing adapted to be removably attached to the compartment, a plurality of compartments in said housing one of which is insaid insulated compartments for drawing air from the vehicle compartment, cooling it and returning it to the vehicle compartment, including an evaporator heat exchanger, means in the other compartments including a gas engine and compressor for causing refrigerant fluid to move to and through the evaporator, and means in the insulated compartment subject to the air pressure therein for causing reversal of flow of the refrigerant through the evaporator heat exchanger to defrost the same.

4. Means for air-conditioning compartments adapted to hold moisture-containing perishables, comprising a housing including an insulated compartment, a blower and evaporator heat exchanger in said insulated compartment, means for defrosting the heat exchanger, a pan in the bottom of the insulated compartment for receiving the water released by defrosting, other means for delivering water to the pan, and an electric heater in the water adjacent the air intake of the fan for releasing water vapor to the air while the fan is in operation.

5. Means for air-conditioning compartments adapted to hold moisture-containing perishables,

, comprising a housing including an insulated compartment, a blower and evaporator heat exchanger in said insulated compartment, means for defrosting the heat exchanger, a pan in the bottom of the insulated compartment for receiving the water released by defrosting, other means for delivering water to the pan, an electric heater in the water adjacent the air intake of the fan for releasing water vapor to the air while the fan is in operation, and a humidostat in the compartment for controlling operation of the electric heater. 1

6. Means for air-conditioning compartments adapted to hold moisture-containing perishables, comprising a housing including an insulated compartment, a blower and evaporator heat exchanger in said insulated compartment, means for defrosting the heat exchanger, a pan in the bottom of the insulated compartment for receiving the water released by defrosting, other means for delivering water to the pan, and a body of fibrous material such as mineral wool in the pan and extending above the surface thereof for holding the water within the pan and for presenting extensive evaporating surface to the current of air moved by the blower.

7. Means for air-conditioning compartments adapted to hold moisture-containing perishables,

sulated from the other compartments. means in comprising means for circulating air in such compartments, means for cooling said air including a compressor and an evaporator heat exchanger having restricted passageways about said heat exchanger through which the circulated air must pass, and a pressure responsive member subject to decreased static pressure of the circulated air caused by icing of said constricted passageways for causing reversal of flow of refrigerant through the evaporator, whereby when such icing and decreased pressure occur defrosting of the heat exchanger will be effected.

8. Means for air-conditioning compartments adapted to hold moisture-containing perishables,

comprising means for. circulating air in such compartments, means for cooling said air including a compressor and an evaporator heat exchanger having restricted passageways about said heat exchanger through which the circulated air must pass, valve mechanism adapted to be shifted to cause-reversal of flow of refrigerant to defrost the evaporator heat exchanger, and a pressure responsive member subject to decreased static pressure of the circulated air caused by icing of the passageways for causing shifting of said valves, whereby when such icing and decreased pressure occur defrosting will be efiected.

9. Means for air-conditioning compartments adapted to hold moisture containing perishables, comprising instrumentalities for cooling'the air within the vehicle compartment including a chamber having therein an evaporator heat exchanger and a second chamber having therein a blower for drawing air through the heat exchanger, means for delivering compressed refrigerant to the evaporator heat exchanger including a valve through which the refrigerant liquidis caused to flow, means including a compressor for eflecting said flow, said valve comprising a movable member having ports and channels cooperating with said last named means for controlling movement of the refrigerant liquid, means for moving the valve to reverse the flow of refrigerant fluid therethrough, and means subject to the static air pressure within the second chamber resulting from operation ,of the blower for rendering the valve moving means operative. 10. Means for air conditioning the storage compartment of a transportation truck, comprising a single unitary casing adapted to be removably mounted as an entirety upon and supported by a wall of the compartment, an insulated chamber formed in said casing, an evaporator in said chamber, a driven blower in the chamber for blowing air through the evaporator, means for placing said compartment in communication with said blower, a driven compressor, a condenser, driven air moving means for the con-.

for stopping and starting the gas engine.

JOSEPH A. NUMERO. FREDERICK M. JONES. 

